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Investigation of composite material degradation indicators using acoustic measurement: comparison with laser vibrometry
Fíla, Tomáš ; Urushadze, Shota ; Kytýř, Daniel ; Valach, Jaroslav ; Šperl, Martin
This paper deals with investigation of acoustic material degradation indicator (attenuation decrement drop of selected natural frequency) measured by a custom-built experimental device. Samples of C/PPS fibre composite material were analyzed. Acoustic signals were recorded and processed using spectral analysis and sound signal regression. Data measured by this method were verified by comparative experiment. Specimens were simultaneously measured using both acoustic experimental device and laser vibrometer. Modal analysis of the specimen were carried out prior to the experiment. This enabled assessment of specimens natural modes and therefore the best impact zone. In total, 10 measurements were performed for each specimen at the same level of degradation. Measured data were then processed and compared. The specimens were repetitively measured after designated number of loading cycles.
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Effect of New Positron Radiopharmaceutical Shielding Equipment on Radiation Load Reduction of PET Centre Personnel.
MAŇASOVÁ, Olga
The bachelor thesis focuses on radiation protection of nuclear medicine personnel while using positron radiopharmaceuticals. The thesis is aimed at evaluating efficient and equivalent doses of PET centre personnel at Na Homolce Hospital where new shielding equipment with an activity dosing device was installed in 2006. Positron radiopharmaceuticals are characterized by emission of 2 annihilation gamma photons of high energy (511 keV) that are created upon interaction of a positron with an electron. Due to the high energies, radiological personnel receives higher radiation loads than upon application of common, particularly technecium-based radiopharmaceuticals used in nuclear medicine. The methodology consists in comparing efficient and equivalent doses before and after installation of the new shielding equipment. On base of results we can state that the doses to personnel were significantly reduced after installation of new shielding equipment. The doses were reduced by half during three years. New shielding is relevant from optimalization of radiation protection perspective. Statistical processing and graphic illustrations form part of the bachelor thesis.
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Comparison of lactate level at the same load in a swimming treadmill and on a bicycle ergometer
Suchomelová, Helena ; Jurák, Daniel (advisor) ; Čechovská, Irena (referee)
3 ABSTRACT Title: Comparison of lactate level at the same load in a swimming treadmill and on a bicycle ergometer Subject: 6 students (3 girls and 3 boys) from the first year of Bachelor's study at the Faculty of Physical Education and Sport of the Charles University at the age of 20,5 years ± 3 years took part in this research. Goal of the research: To compare demands of the load in the swimming flume with the same load on the bicycle ergometer, mainly at the level of the anaerobic threshold. Methods: We tested students by the method Critical Swimming Speed (CSS) for finding out their anaerobic threshold. Then students swam physical tests in the swimming treadmill - flume. The test consists of three 6 min parts. The first part of the swimming test was under the level of the CSS, the second part was at the level of the CSS and the third part was above the level of the CSS. We used the device for measuring the beat frequency (sport-testers) for obtaining information about changes of the heart rate (HR) during tests. Afterwards we accomplished tests on the bicycle ergometer, where we maintained HR at the same levels as in the load in the flume. We measured level of blood lactate (LA) after every 6 min part in the flume and on the ergometer. We statistically processed resulted values of LA by the Wilcoxon...
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Investigation of friction effect on a blades model
Půst, Ladislav ; Horáček, Jaromír ; Veselý, Jan
The blades model consists of two steel beams with rectangular cross-sections, fixed to the masive block. A loading device for normal force in the friction contact, exciting system and variouspickups togeteher with accessory apparatuses for evaluation and recordng completes the measurement set-up. The dynamic stiffnes, lost energy and equivalent coefficient of damping were ascertained. The found influences of normal force, excitation apmplitude and frequency on the reduction of both beams vibration amplitudes form a base for optimal destign of friction elements.
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Stress-strain behaviour research of rocks under dynamic loading
Petroš, V. ; Bagde, M. N. ; Daněk, T. ; Hofrichterová, L. ; Hudeček, V. ; Michalčík, P. ; Slivka, V. ; Špinka, O. ; Vavro, M. ; Žůrek, P. ; Holub, Karel
The aim of this project was oriented to determination of physical-mechanical characteristics of rocks under dynamic load using laboratory device MTS 816 Rock Test System. The research was drawn to investigation of surrounding rocks properties, i.e. rocks from the rock massif, where anomaleous geomechanical events do occur.
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Dynamic impact wear testing of nanostructured coatings
Boušek, Jaroslav ; Sobota, Jaroslav
Successive impacts of the cemented carbide ball onto a film coated sample induce high contact loads, which can vary in amplitude depending on the probe mass and the velocity of the probe immedialtely before the stroke. The method permits the variation of the impact force, the impact frequency and the number of impacts. Thus it is possible to quantify the number of the load cycles which a coated component can withstand and define a critical fatigue force. A simple probe including electronic circuity for this method use was designed. The basic equipment scheme and example of measurement are given.
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Electrothermal vaporization
Dočekal, Bohumil
Utilization of various electrothermal vaporizaton (ETV) devices for sample introduction in inductively coupled plasma based atomic spectrometry methods is discussed. Optimum experimental conditions and design of ETV devices is stressed with respect to transport efficiency of sample introduction, to plasma loading, possible interferences etc.
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Dysmetabolic mechanism for defining metabolit syndrome.
Karaščák, Roman ; Semecký, Vladimír (advisor) ; Martiník, Karel (referee)
5 Abstract of diploma thesis Author: Roman Karaščák Title: Dysmetabolic mechanism in the definition of metabolic syndrome Diploma thesis Charles University in Prague, Faculty of Pharmacy in Hradec Kralove Field of Study: Pharmacy The aim of this thesis is to assess the significance of insulin resistance in the pathophysiology of metabolic syndrome by measuring levels of the body fat burning during fasting and during the oral glucose tolerance test (OGTT). Next, we tried to establish a typology of different insulin groups. Under this classification, we expect identification of stage of pathology of the metabolism by insulin response to glucose load and the consequent effect on tissue metabolism. The experiment included 273 subjects who underwent OGTT and evaluation of the current fat burning device DeltatracTM . The withdrawn blood samples were determined in order to provide levels of insulin and c-peptide by methods imunoradiometric determination/analysis (IRMA). The determined values were statistically processed in order to assess particular relationships. Results section describes the obtained relations. We found BMI dependence on fasting and glucose induced inzulinemy. Dependence of the energy use of fats on inzulinemy was not proven. Next, we made a proposal insulin typology. In conclusion, the study of...
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Health center
Dawid, Lukáš ; Hazucha, Juraj (referee) ; Donaťáková, Dagmar (advisor)
Diploma thesis designs a barrier free new building of medical devices – policlinic (health center) with 14 medical workplaces. Object has three floors and basement. The building is covered by a vegetation flat roof. Building of policlinic is based on strip foundations and load-bearing walls are made from sand-lime blocks. Horizontal systém is created like reinforced concrete ceiling and in the same way internal staircase. The building is design at passive architecture – have compact form, thick layer of insulation and airtight cover. The main glass facade is oriented to the sout. There is used heat recovery air conditioning and heat pumping for heating in building. Health center satisfy currently legislation.
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Deformation behaviour of gellan gum based artificial bone structures under simulated physiological conditions
Krčmářová, N. ; Šleichrt, J. ; Fíla, Tomáš ; Koudelka_ml., Petr ; Kytýř, Daniel
The paper deals with investigation of deformation behaviour of gellan gum (GG) based\nstructures prepared for regenerative medicine purposes. Investigated material was synthesized as porous spongy-like scaffold reinforced by bioactive glass (BAG) nano-particles in different concentrations. Deformation behavior was obtained employing custom designed experimental setup. This device equipped with bioreactor chamber allows to test the delivered samples under simulated physiological conditions with controlled flow and temperature. Cylindrical samples were subjected to uniaxial quasi-static loading in tension and compression. Material properties of plain scaffold buffered by 50 wt% and 70 wt% BAG were derived from a set of tensile and compression tests. The results are represented in form of stress-strain curves calculated from the acquired force and displacement data.
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